UNITED STATES ENVIRONMENTAL PROTECTION AGENCY REGION 10 1200 Sixth Avenue, Suite 900 Seattle, WA 98101-3140 

# UUN 14 2DiC REGIONAL ADMINISTRATOR

Toni Hardesty, Director Department ofEnvironmental Quality State ofIdaho 1410 North Hilton Boise Idaho, 83706
Dear DirectorHardesty:
Thank you for yourrecommendations on air quality designations for the revised National Ambient Air Quality Standards (NAAQS) for lead throughout Idaho. Reducing levels oflead pollution is an important part ofEPA's commitmentto a clean, healthy environment. Lead exposure can cause a range ofadverse health effects, most notably in children. Exposures to low levels oflead early in life have been linked to effects on IQ, learning, memory and behavior. This letter is to notify you ofthe U.S

.Environmental Protection Agency's (EPA's) response to Idaho's designation recommendations, and to inform you ofour approach for completing the designations for the revised lead NAAQS.
On October 15,2008,EPA substantially strengthened NAAQS for lead. The new standards, set at 0.15 micrograms percubic meter (!lg/m3), are 10 times tighter than the previous standards. In conjunction with strengthening the lead NAAQS, EPA also established new criteria for siting ambient lead monitors. The pre-existing ambient lead monitoring network was inadequate for determining whethermany areas are meeting the revised lead NAAQS. Monitors meetingthe new network sitingrequirements were to begin operation January 1,2010.
The Clean Air Act (CAA) requires EPA to complete the initial designation process within two years ofpromUlgating a new orrevised NAAQS. Ifthe Administrator has insufficient information to make these designations, EPA has the authority to extend the designation process by up to one year. In light ofthe new monitoring network which will generate additional information in the upcoming year, EPA intends to complete the lead designations in two rounds. In the first round, to be completed by October, 15, 2010, EPA is designating as "nonattainment" any area that is violating the 2008 lead NAAQS based on data from the pre-201O monitoring network. Forall other areas, EPA is extending the deadline for designations by up to one year so that data from the newly deployed monitors can beconsidered in making appropriate designation decisions. EPA will complete the second round oflead designations no later than October 15, 2011.
We have reviewed Idaho's September 30,2009,recommendation letter on air quality designations and all the associated technical information for the 2008 lead NAAQS, including, if available, the most recent airquality data from 2007-2009. However, EPA is not intending to complete the initial area designations for your state at this time. Instead, EPA intends to designate all areas in your state by no later than October 15, 2011, in the second round oflead designations. Ifyou would like to submit updated recommendations for your areas for our

() PrintedonRecycledPaperconsideration in the second round ofdesignations, we request that you do so byDecember 15, 2010. Forthe second round ofdesignations, we will notify all states and tribes ofour preliminaryresponses to theirrecommendations by no laterthan June 17,2011.
We look forward to a continued dialogue with you and your staffas we work together to implement the 20081eadNAAQS. Should you have any questions, please do not hesitate to call me, orhave your staffcontact Steve Bodyin the Office ofAir, Waste and Toxies at 206-553-0782. Sincerely, 

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Dennis 1. McLerran Regional Administrator
Enclosure

cc: Martin Bauer, Air Quality Division Administrator GinaMcCarthy, Assistant Administrator for Air and Radiation Steven D. Page, Director, Office ofAir QualityPlanning and Standards



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